Rectangular-piston pump



March 29, 1966 w. D. KOMHYR 3,242,869

RECTANGULAR-TING! PUMP Filed July 15, 1964 I 2 Sheets-sheet 1 INVENTOR AGENT March 29, 1966 w. D. KOMHYR 3,242,859

RECTANGULAR'w-PISTQN rum Filed July 15, 1964 Y Y 2 Sheets-Sheet 2 QINVENTOR' Wal te D'Komhyr- United States Patent 3,242,869 RECTANGULAR-PISTON PUMP Walter D. Komhyr, 4343 Lee Highway, Arlington, Va. Filed July 15, 1964, Ser. No. 382,977 6 Claims. (Cl. 103159) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon, in accordance with the provisions of 35 United States Code (1952), Section 266.

This invention relates to a pump having a piston and cylinder of rectangular cross section.

An object of this invention is to provide a pump in which the friction between the piston and cylinder is minimized.

Another object of this invention is to provide a pump in which the fit between the piston and cylinder is readily adjustable.

. -Another object is to provide a pump in which the .piston and cylinder may be constructed of self-lubricating .materials,

Still another object is to provide a pump in which the piston and cylinder may be constructed of chemicallyinert materials.

A further object is to provide a pump which can handle corrosive fluids.

destroy atmospheric ozone when used to sample the atmosphere.

.A still further object is to provide a pump which is mechanically simple, reliable, rugged, compact and economical. In accordance with the principles of the present invention, an elongated cylinder plate is provided with a longitudinally-extending slot of uniform rectangular cross section, into which is fitted a piston of substantially the 'same cross section. The cylinder plate is disposed between a pair of cover plates which overlay the slot and thereby. form a cylinder chamber. A piston shaft extends through the'cover plates and piston. One end of the elongated cylinder plate is moved over a circular path in a plane parallel to the plane of said plate, while the cover plates are held stationary. Consequently, the cylinder plate reciprocates with respect to the piston, which in turn rocks with respect to the cover plates about the piston shaft. Disposed in one of the cover plates are inlet and outlet ports which alternately communicate with the .slot as it rocks about the piston shaft.

The above and other objects, features and advantages -of the present invention will be apparent as the following description is read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view, sectioned in part, of a pump embodiment constructed in accordance with the 'present invention;

FIG. '2 is a sectional view taken on the vertical midline "of the pump of FIG. 1; FIG. 3 is a front eleva'tional view of the pump of FIG. 1, the mounting plate and motor being omitted therefrom, and portions of the cover plate and cylinder "plate being broken away to show the pump ports, the

cylinder plate being at its lowest position;

FIGS. 4, 5 and 6 are additional front elevational views, similar to FIG. 3, but showing the cylinder plate at three other positions; FIG. 7 is an exploded view of the pump piston plate and its insert and spring;

FIG. 8 is a side elevational view of the piston plate; FIG. 9 is an enlarged perspective view of the right- "hand port of the pump; and

3,242,869 Patented Mar. 29, 1966 FIG. 10 is a front eleva-tional view of a dual-cylinder pump embodiment of the present invention.

The pump illustrated in FIGS. 1 and 2 includes a rigid mounting plate 11 which supports a piston shaft 12 and crankshaft 13 in a parallel, spaced-apart manner, each shaft being perpendicular to the mounting plate 11. The piston shaft 12 has a threaded portion 14 and screw head 15 adapted to engage a tapped hole in the mounting plate 11, while crankshaft 13, which comprises the armature shaft of a small electric motor 16 secured to the back of the mounting plate 11, rotatably extends through a hole in the mounting plate 11. The crankshaft 13 drives a disc-shaped crank arm 17 carrying a conventional crank pin 18.

A base plate 20 having a hole adapted to pass the piston shaft 12 is secured in any convenient manner, as by gluing, to the front of the mounting plate 11. Disposed against the base plate 20 is a small, generally rectangular-shaped piston plate 21, which has a centrallylocated hole adapted to swing freely about the piston shaft 12, as illustrated in FIGS. 3-6. The piston plate 21 fits into a slot 22 disposed longitudinally in an elongated cylinder plate 23 of substantially the same thickness as the piston plate 21. The width of the slot 22 is substantially identical to the width of the rectangular piston plate 21, whereby the cross sections of the slot 22 and piston plate 21 are substantially identical.

The top end of the cylinder plate 23 is rotatably connected to the crank pin 18. As the crank arm 17 is rotated by the crankshaft 13, the cylinder plate 23 is caused to reciprocate with respect to the piston plate 21. The piston plate 21 in turn rocks or swings about the piston shaft 12, as may be seen from FIGS. 3-6.

It will be evident that the length of the slot 22 should at least equal the length of the rectangular piston plate 21 plus twice the length of the crank arm 17. The area of the base plate 20 should be sufiicient to extend under the lower portion of the slot 22 at all positions of the cylinder plate 23.

As shown in FIG. 3, a pair of elongated, parallel ports 25, 27 is disposed in the base plate 20. The ports 25, 27 are symmetrically arranged about a line connecting the piston shaft 12 and the crankshaft 13, and are spaced apart a distance slightly greater than the width of the slot 22 in the cylinder plate 23, .so that the slot 22 can overlay only one (or neither) of the ports 25,27 at any of the positions of the cylinder plate 23. The ports 25, 27 each extend from adjacent the lower edge of the piston plate 21 a distance substantially equal to twice the length of the crank arm 17, as measured in the direction away from the piston shaft 12.

Referring to the detailed viewof FIG. 9, it will be seen that the port 27 extends part way into the thickness of the base plate 20. A short, narrow passageway 28 connects into the side of the port 27 and leads to a larger passageway 29, adapted to engage a conduit such as a piece of flexible tubing. The port 25 is provided with corresponding passageways 31, 32, as shown in FIGS. 26.

A cover plate 35, FIGS. 1-3, having a hole adapted to pass the piston shaft 12 is disposed against the cylinder plate 23 and piston plate 21. The area of this cover plate 35 should be suflicient to always cover the slot 22 in cylinder plate 23 as the cylinder plate moves in the manner described above.

The cover plate 35 preferably is laminated in structure, the layer of material 36 (FIG. 2) adjacent the piston and cylinder plates 21, 23 being a bearing type material, while the outer layer 37 comprises a more rigid, load-supporting material. 1

As shown in FIGS. 2 and 3, the cover plate 35 is pre vented from rotating about the piston shaft 12 by means of an anchor bolt 40 that extends through a second hole 41 provided in the cover plate 35. The anchor bolt 40 conveniently is located along a line connecting the piston shaft 12 and crankshaft 13, and is slightly spaced from the top edge of the piston plate 21, so that it does not interfere with the rocking motion of the piston plate 21 about the piston shaft 12.' The length of the slot 22 in cylinder plate 23 should be adapted to provide clearance for the anchor bolt 40 when the cylinder plate 23 is at its lowest position, shown in FIG. 3. Referring to FIG. 2, it willbe seen that the anchor bolt 40 conveniently is provided with a threaded portion 42 which engages a tapped hole in the mounting plate 11.

A spiral spring 45, FIGS. 1 and 2, is disposed on the piston shaft 12. The inner end of the spring 45 bears against a lever bar 46, and a nut 47 threaded onto the free end of the piston shaft 12 adjustably bears against the outer end of the spring 45. The lever bar 46 has a hole intermediate its ends for freely passing the piston shaft 12. The upper end of the lever bar 46 has an indentation 48, FIG. 2, adapted to pivot on the end of the anchor bolt 40, while the lower inside end of the lever bar has a raised portion 49 which bears against the cover plate 35 over the lower end of the piston plate 21. Under the urging of spring 45, the lever bar 46 causes the cover plate 35 and base plate 20 to firmly press against the op posite sides of the piston and cylinder plates 21, 23, thereby assuring a fluid-tight cylinder chamber. The degree of pressure or friction between the cylinder-piston plates 21, 23 and the base-cover plates 20, 35 is readily adjustable by the nut 47.

The pivot indentation 48, FIG. 2, of lever bar 46 is adapted to allow air to leak around the anchor bolt 40, via the hole 41 in the cover plate 35, into the slot 22 adjacent the top of the piston plate 21 and thereby prevent the formation of a vacuum or pressure in the top of the slot 22 as the cylinder plate 23 is moved as described previously. As shown in FIGS. 4-6, the top of the slot 22 does not overlay the base plate 20 during most of the travel of the cylinder plate 23 whereby the air leak around anchor bolt 40 is necessary only during a small amount of the travel of cylinder plate 23.

It will be observed in FIGS. 3-6 that the generally rectangular-shaped piston plate 21 has an insert 50. As shown in detail in FIGS. 7 and 8, the piston plate 21 has a channel 51 disposed across the thickness thereof, along one of the long sides and near the top edge of the piston plate. The insert 50 has substantially the same dimensions as the channel 51, and is biased outward from the channel by a small spiral spring 52 disposed in a well 53 extending from the bottom of the channel 51 part way into the piston plate 21. The insert 50 bears against the slot 22, FIGS. 36, and thereby assures that the piston plate 21 maintains a fluid-tight seal with the cylinder plate 23 as the cylinder plate 23 reciprocates with respect thereto.

From the foregoing, the operation of the pump illustrated in FIGS. 19 will be evident. Rotation of the crankshaft 13 causes the crank pin 18, and the upper end of the cylinder plate 23 rotatably connected thereto, to describe a circular path with respect to the base plate 20 and cover plate 35. The lower portion of the cylinder plate 23 is constrained to reciprocate about the piston plate 21 by the slot 22, and the piston plate 21 in turn is constrained to rock about the piston shaft 12. As shown in FIG. 3, when the crank pin 18 is at its lowest position, the slot 22 is midway between the ports 25, 27; and, the cylinder chamber defined by the slot 22 and piston plate 21 is a maximum. When the crankshaft 13 is rotated clockwise ninety degrees, the cylinder plate 23 assumes the position shown in FIG. 4, wherein the slot 22 is in communication with port 27 and the cylinder chamber has been reduced in volume. Port 27 thus comprises the exhaust or outlet port of the pump when the crankshaft 13 is ro ated clockwise.

When the crankshaft 13 is rotated an additional ninety degrees, the cylinder plate 23 assumes the position shown in FIG. 5, wherein the slot 22 is switching communication from the outlet port 27 to the other (inlet) port 25, the volume of the cylinder chamber being a minimum. FIG. 6 shows th ecylin-der plate position corresponding to another ninety degrees of rotation of the crankshaft 13. In FIG. 6 the slot 22 is in communication with the inlet port 25 and the volume of the cylinder chamber is increasing, whereby the pump is on the intake stroke.

The preferred material for constructing the base plate 20, piston plate 21, insert 50, cylinder plate 23, and layer 36 of the cover plate 35 is a self-lubricating material, such as poly-tetrafluorethylene (Teflon); however, ordinary metallic or resinous materials may also be used, if the pump is suitably lubricated. An especially preferred selflubricating material is Teflon reinforced about 10% to about 25% by weight with glass fibers. Teflon materials are obviously advantageous in that they enable the pump to handle corrosive fiuids. In addition, the use of these materials enables the pump to be utilized in apparatus de' signed to sample the atmosphere for ozone content. As is well known, Teflon when suitably cleaned and ozonized does not destroy (react with) the minute amounts of ozone present in the atmosphere. Since .Tefion is selflubricating, the pump does not require lubricants, most of which also tend to destroy atmospheric ozone. Hence the pump of FIGS. 19 is especially adapted for use in an atmospheric ozone sensor. The pump is relatively inexpensive, is easily adjusted for various pressure differentials, is rugged and compact.

FIGURE 10 illustrates a dual-cylinder embodiment of the pump of the present invention. In this embodiment, an enlarged base plate 60 is provided with four ports 61- 64 adjacent the four corners of a rectangular-shaped piston plate 65. The ports 61 and 63 are spaced from the ports 62 and 64 a distance slightly greater than the width of the piston plate 65; each of the ports 61-64 extends a distance substantially equal to twice the length of the crank arm 17.

The piston plate 65, which rocks about the piston shaft 12, is fitted into the slot 22 in a cylinder plate 66 which is rotatably connected to the crank pin 18. Disposed on the piston and cylinder plates 65, 66 is a cover plate 67 which has a hole through which the piston shaft 12 ex-. tends. To prevent the cover plate 67 from rotating about the piston shaft 12, an anchor bolt 70 is arranged to extend from the base plate 60 and engage a laterally-projecting ear 71 of the cover plate 67. The cover plate 67 is urged toward the base plate 60 by a spring and nut arrangement (not shown) similar to the spring-nut arrangement 45, 47 illustrated in FIGS. l9, the lever bar 46 being omitted in this embodiment.

The operation of the dual-cylinder pump of FIG. 10 is identical to the operation of the pump of FIGS. 1-9, except that the upper portion of the slot 22 in the cylinder plate 66 also communicates with the ports 63, 64 as the lower portion of the slot 22 communicates with the ports 61, 62 as described in connection with the ports 25, 27 of FIGS. l9. When the crankshaft 13 rotates clockwise, it is evident that ports 61 and 63 comprise inlet ports, in that the cylinder chambers are increasing in volume when the slot 22 overlays these ports. Conversely, ports 62 and 64 comprise outlet ports. As will readily be appreciated, the ports 61 and 63 may be utilized separately from each other or they may be connected in parallel, either by external tubing or by passageways formed in the base plate 60. The ports 62, 64 likewise may be utilized independently or in parallel, as desired.

The present invention has been described by way of specific illustrative embodiments. It will be readily apparent to those skilled in the art that many modifications and variations of the specific embodiment'may be designed to suit the application at hand. Accordingly, it is intended th t the in en i n cover all such modifications and variations as fall within the scope and meaning of the appended claims.

What is claimed is:

1. A pump comprising, a rigid mounting plate, a crankshaft mounted for rotation through said mounting plate, a crank arm connected to said crankshaft, a crank pin connected to said crank arm, a piston shaft attached to said mounting plate and extending parallel to said crankshaft, a base plate secured to said mounting plate with said piston shaft extending through a hole therein, a substantially rectangular-shaped piston plate disposed against said base plate with said piston shaft rotatably extending through a centrally-located hole therein, elongated inlet and outlet ports disposed in said base plate symmetrically about a line connecting said crankshaft and said piston shaft, said ports being spaced apart a distance slightly greater than the width of said piston plate and extending from adjacent the corners of said piston in the direction away from said piston shaft a distance equal to substantially twice the length of said crank arm, an elongated cylinder plate of the same thickness as said piston plate and having a longitudinally-extending slot of substantially the same width as said piston plate disposed against said base plate with said piston plate disposed in said slot, the length of said slot being equal to at least the sum of the length of said piston plate and twice the length of said crank arm, one end of said elongated cylinder plate being rotatably connected to said crank pin, a cover plate disposed against said cylinder plate and piston plate with said piston shaft extending through a hole therein, a spring disposed around said piston shaft, the free end of said piston shaft being threaded, a nut engaging said threaded free end, an anchor bolt extending between said mounting plate and said cover plate to prevent rotation of said cover plate about said piston shaft.

2. A pump as set forth in claim 1, wherein said anchor bolt is disposed along a line connecting said piston shaft and said crankshaft, said anchor bolt extending through a hole in said cover plate, a lever bar having a hole for passing said piston shaft disposed between said spring and said cover plate, one end of said lever bar having an indentation for pivoting on said anchor bolt, the other end of said lever bar having a raised portion for bearing against said cover plate over the end of said piston plate.

3. A pump as set forth in claim 1, wherein said piston plate has a channel disposed across the thickness thereof along one of the long sides thereof, a well extending from the bottom of said channel part way into said piston plate, a spring disposed in said Well, an insert of substantially the same dimensions as said channel disposed in said channel, said spring urging said insert from said channel so as to seal said piston plate in said slot in said cylinder plate.

4. A pump as set forth in claim 3, wherein said base plate, piston plate, cylinder plate, cover plate and insert are constructed from a self-lubricating material.

5. A pump as set forth in claim 4, wherein said material is polytetrafluorethylene.

6. A pump as set forth in claim 5, wherein said polytetrafluorethylene is reinforced about 10% to about 25% by Weight with glass fibers.

References Cited by the Examiner UNITED STATES PATENTS 395,039 12/1888 Dake 103163 3,059,586 10/ 1962 Brailsford 103-159 FOREIGN PATENTS 59,077 9/ 1941 Denmark. 592,432 9/1947 Great Britain. 655,343 7/1951 Great Britain.

SAMUEL LEVINE, Primary Examiner.

H. F. RADUAZO, Assistant Ex miner. 

1. A PUMP COMPRISING, A RIGID MOUNTING PLATE, A CRANKSHAFT MOUNTED FOR ROTATION THROUGH SAID MOUNTING PLATE, A CRANK ARM CONNECTED TO SAID CRANKSHAFT, A CRANK PIN CONNECTED TO SAID CRANK ARM, A PISTON SHAFT ATTACHED TO SAID MOUNTING PLATE AND EXTENDING PARALLEL TO SAID CRANKSHAFT, A BASE PLATE SECURED TO SAID MOUNTING PLATE WITH SAID PISTON SHAFT EXTENDING THROUGH A HOLE THEREIN, A SUBSTANTIALLY RECTANGULAR-SHAPED PISTION PLATE DISPOSED AGAINST SAID BASE PLATE WITH SAID PISTON SHAFT ROTATABLY EXTENDING THROUGH A CENTRALLY-LOCATED HOLE THEREIN, ELONGATED INLET AND OUTLET PORTS DISPOSED IN SAID BASE PLATE SYMMETRICALLY ABOUT A LINE CONNECTING SAID CRANKSHAFT AND SAID PISTON SHAFT, SAID PORTS BEING SPACED APART A DISTANCE SLIGHTLY GREATER THAN THE WIDTH OF SAID PISTON PLATE AND EXTENDING FROM ADJACENT THE CORNERS OF SAID PISTON IN THE DIRECTION AWAY FROM SAID PISTON SHAFT A DISTANCE EQUAL TO SUBSTANTIALLY TWICE THE LENGTH OF SAID CRANK ARM, AN ELONGATED CYLINDER PLATE OF THE SAME THICKNESS AS SAID PISTON PLATE 